diff options
Diffstat (limited to 'sys/vm/vm_glue.c')
| -rw-r--r-- | sys/vm/vm_glue.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/sys/vm/vm_glue.c b/sys/vm/vm_glue.c index 9deb363..3843ecd 100644 --- a/sys/vm/vm_glue.c +++ b/sys/vm/vm_glue.c @@ -70,6 +70,8 @@ __FBSDID("$FreeBSD$"); #include <sys/mutex.h> #include <sys/proc.h> #include <sys/resourcevar.h> +#include <sys/sched.h> +#include <sys/sf_buf.h> #include <sys/shm.h> #include <sys/vmmeter.h> #include <sys/sx.h> @@ -239,6 +241,76 @@ vsunlock(void *addr, size_t len) VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); } +/* + * Pin the page contained within the given object at the given offset. If the + * page is not resident, allocate and load it using the given object's pager. + * Return the pinned page if successful; otherwise, return NULL. + */ +static vm_page_t +vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset) +{ + vm_page_t m, ma[1]; + vm_pindex_t pindex; + int rv; + + VM_OBJECT_LOCK(object); + pindex = OFF_TO_IDX(offset); + m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); + if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { + ma[0] = m; + rv = vm_pager_get_pages(object, ma, 1, 0); + m = vm_page_lookup(object, pindex); + if (m == NULL) + goto out; + if (m->valid == 0 || rv != VM_PAGER_OK) { + vm_page_lock_queues(); + vm_page_free(m); + vm_page_unlock_queues(); + m = NULL; + goto out; + } + } + vm_page_lock_queues(); + vm_page_hold(m); + vm_page_wakeup(m); + vm_page_unlock_queues(); +out: + VM_OBJECT_UNLOCK(object); + return (m); +} + +/* + * Return a CPU private mapping to the page at the given offset within the + * given object. The page is pinned before it is mapped. + */ +struct sf_buf * +vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset) +{ + vm_page_t m; + + m = vm_imgact_hold_page(object, offset); + if (m == NULL) + return (NULL); + sched_pin(); + return (sf_buf_alloc(m, SFB_CPUPRIVATE)); +} + +/* + * Destroy the given CPU private mapping and unpin the page that it mapped. + */ +void +vm_imgact_unmap_page(struct sf_buf *sf) +{ + vm_page_t m; + + m = sf_buf_page(sf); + sf_buf_free(sf); + sched_unpin(); + vm_page_lock_queues(); + vm_page_unhold(m); + vm_page_unlock_queues(); +} + #ifndef KSTACK_MAX_PAGES #define KSTACK_MAX_PAGES 32 #endif |
